känna till in English:

Do you really need to ask the question to know the answer?

I know.

Tom can meet you at the airport if you let him know your arrival time.

Tom claimed that he didn't know his beach house was being used for illegal activities.

The most interesting information comes from children, for they tell all they know and then stop.

I just want to let you know that I can't attend this afternoon's meeting.

I'm a foreigner and I don't know Czech very well. Please, speak slowly.

Who is the wisest person you know?

You must remember to tell him all that you know.

He may be a good man for all I know.

I may seem confident, but I get extremely nervous speaking in front of people. My hands tremble, I get all tongue-tied, and sometimes I don't even know what I'm saying myself.

I would like to know how these substances are absorbed by the body.

I didn't know hummingbirds could even fly upside down when frightened.

If I drop out of contact, let the police know, OK?

The people in the room all know one another.